@gotoluc

OK, thanks for the bucking explain. I see that you consider this as a bucking effect and also understand that there is no relation between this and the standard bucking coils that are generally wound on a same core. Great.

Coils are wound on a core so you have the core layer that starts the winding and the outer layer that ends the winding.

A) The "pulse side" is the side of your parallel primaries that gets the make break, what ever it is - positive or negative of a source, applied to the coil at the core or outer layer.
B) The "always connected side" is the side of your parallel primaries that is always connected to source - positive or negative, applied to the coil at the core or outer layer.

So what I am trying to explain is that you add a third MOT primary in series to the two in parallel on the always connected side. This third one is just there sitting on the table and does not have to be mounted in any way on your wheel. Depending on which side is pulsed, these are the two possible ways;

                                           ====Primary 1====
----  pulsed on positive ---F--                                 ====Primary 3==== ----- constant negative------
                                           ====Primary 2====
or,

                                            ====Primary 1====
----  pulsed on negative --F---                                 ====Primary 3==== ----- constant positive------
                                            ====Primary 2====

OK, so where are you connecting your flyback diode? Using the above scheme, the flyback diode should come off the line where you see the letter F, that is between the pulse and the two parallel primaries.

So here are two questions for you guys about flyback.

1) If you run an electric motor or transformer with AC, A) is there flyback, or, B) is flyback strictly present after a DC pulse only?
2) If #1 is A or B or both, why?

wattsup

I'll give it a test at some point and let you know. You should see the result in about a week, if I forget please remind me.

Thanks for sharing

Luc

Hi wattsup,

My "2 cents" answers  on your questions. I repeat here your questions:

"1) If you run an electric motor or transformer with AC, A) is there flyback, or, B) is flyback strictly present after a DC pulse only?
2) If #1 is A or B or both, why?"

Answers:
1) I do not think there is flyback with AC input so my aswer is B

2) only the B because with a normal (50 or 60 Hz or whatever frequency) sinusoidal input voltage there is no interruption of the input current (zero crossing yes but it is not sudden).  Flyback pulse is strictly associated with a switch-off event under which no input current is drawn from the the input source which normally provides the input current during the ON times.  Again, the zero crossing event is not equivalent at all with a switch-off event by a dedicated switch.

Regarding your suggestion on using a 3rd primary MOT coil in series with the paralleled ones:  the use of this coil increases the overall impedance of the whole setup and as such you have to increase a little the input voltage to compensate for the reduced input current what this increased impedance causes. It is okay that you would receive flyback energy from the 3rd coil too, question is would this give more juice than what the increased input cost?  needs testing.

You wrote earlier that the 10 V or so input voltage level is rather low with respect to the mains 110-120 V these MOT primary coils were designed for originally. Here comes again that Luc drives these coils with pulsed DC and not AC, notice the pulsed DC involves already several Amper peak currents when the voltage level is at the 10 V area, while normal AC drive at 110-120 V input would result only in some hundred mA maximum or less input current levels (assuming no load condition).

One more thing: these "transformers" have open magnetic cores, rendering the original primary coil inductances much less than a closed core insures, and add to this the bucking magnetic coupling which further reduces the resulting inductance. The I core entering the gap between the two open cores increases this lowered coil inductance as we learnt from Luc inductance measurements, this is good.

Gyula

Hi MileHigh,

I would like to understand what you mean by magnetic fields cancelling each other out when the coils have air between them?

I think that bucking or repelling magnetic fields try to push away each other, towards sideways. The closer to each other the repel poles get,
the more compressed (squeezed) the fields become and they come out from the gap towards sideways and then spread out again.

Long time ago I downloaded from a now defunct yahoo group some measured flux data (collected by a flux meter probe) on the surface of
ceramic magnets that included the repel mode between them too, see attached. (I cannot recall who uploaded it back then, unfortunately.)
In those measurements the magnets were fully pressed to touch each other surfaces when they were in repel mode. It is interesting that
the squeezed-out North fields have more than twice measured field values on the touching surfaces than the sum of the
two North field values of the individual magnets.

When there is a small air gap left between the facing surfaces, (still no entering slab of metal),  the flux from both magnets should be there
(albeit in a less squeezed form) and repel force would still be there of course between the facing cores as per the gap size would control it.

When the slab of metal approaches the two magnetically bucking cores, the bucking fields from both cores will attract the slab
(more or less equally if their fields are pretty close to each other in strength).

So how do you mean the magnetic fields cancelling each other out when the coils have air gap between them?

Thanks
Gyula

Gyula,

I think that you are just forgetting the basics for a momentary lapse.  The only thing that two separate magnetic fields do is vector addition.  So for those that may not understand that means the two magnetic fields act like the other field doesn't even exist, the two fields just pass right through each other.  You just add the two fields together to get the net magnetic field.

So, if you have a magnetic field going horizontally left to right, and another magnetic field going horizontally right to left, you just add them together.  Because of their respective directions, they cancel each other out.

Therefore, there is no squeezing or compressing going on like you are alluding to.  The people in the Yahoo group led themselves down the proverbial garden path.

Okay, in the next posting let me deconstruct the image you posted from the Yahoo group.

MileHigh

Hi MileHigh,

I would like to understand what you mean by magnetic fields cancelling each other out when the coils have air between them?

When there is a small air gap left between the facing surfaces, (still no entering slab of metal),  the flux from both magnets should be there
(albeit in a less squeezed form) and repel force would still be there of course between the facing cores as per the gap size would control it.

When the slab of metal approaches the two magnetically bucking cores, the bucking fields from both cores will attract the slab
(more or less equally if their fields are pretty close to each other in strength).

So how do you mean the magnetic fields cancelling each other out when the coils have air gap between them?

Thanks
Gyula

Let's do a thought experiment that anybody can replicate in real life.  You have two long and thin bar magnets, where one is slightly stronger than the other.

You set up the magnets like this:   [S============N]        [N=============S]

As the two magnets are brought together you feel increasing repulsion.  Then at a certain close distance from each other you feel nothing, no repulsion or attraction.  That is where the opposing north fields have cancelled each other out.  Then as you bring the two magnets closer together they are lightly attracted and the two north ends stick together.  This is where the stronger magnet has dominated over the weaker magnet and there is a small net magnetic field and a small attraction.

From the side view in Luc's setup, looking at a cross-section, you have two "E" cores facing each other.

If the metal slab is not between the cores, you have a wide air gap between the cores.  In this case much less flux produced by one core crosses the air gap and goes into the facing core.  Nonetheless, some flux will cross over into the facing core.  Whatever flux produced by the left core that goes into the right core will cause cancellation in the flux produced by the right core.  Likewise, whatever flux produced by the right core that goes into the right core will cause cancellation in the flux produced by the left core.

When the metal slab is in place, there is much less of a reluctance gap between the two "E" cores and therefore there will be correspondingly more flux going from the left core into the right core, and vice versa.  Hence, less overall inductance, less attraction for the slab, and more of the wire proportionally in the pair of coils that only functions like a resistor and not like an inductor.

If the two "E" cores produce additive magnetic fields, then one must assume that the attraction of the slab will be that much stronger and presumably balanced enough so that the slab does not scrape against one of the "E" cores.  In effect, for this setup, and for the bucking setup, the slab is dragged down into the bottom of a magnetic potential well, and then at TDC (or just before TDC) you stop energizing the coils to make the magnetic potential well disappear.  If the two coils are additive instead of bucking, one assumes that the slab will fall into a much deeper magnetic potential well and have much more kinetic energy as a result of the steeper fall into the well.

I asked Luc to try an additive instead of a bucking configuration but I don't think the question was acknowledged.  I would be very surprised if I missed something in my analysis.  From what I can see bucking coils in this configuration will work, but not be nearly as well as additive coils.  The wild card is that with the stronger magnetic forces, will the slab hit one of the "E" cores or not?

MileHigh

@gyulasun

Thanks for your comments and I will answer them in bold.

Hi wattsup,

My "2 cents" answers  on your questions. I repeat here your questions:

"1) If you run an electric motor or transformer with AC, A) is there flyback, or, B) is flyback strictly present after a DC pulse only?
2) If #1 is A or B or both, why?"

Answers:
1) I do not think there is flyback with AC input so my answer is B

2) only the B because with a normal (50 or 60 Hz or whatever frequency) sinusoidal input voltage there is no interruption of the input current (zero crossing yes but it is not sudden).  Flyback pulse is strictly associated with a switch-off event under which no input current is drawn from the the input source which normally provides the input current during the ON times.  Again, the zero crossing event is not equivalent at all with a switch-off event by a dedicated switch.


Thank you very much for your answers which where exactly as one would hope to have in our present days.
My answer is written but is too long and I do not want to clutter @gotolucs' thread. haha
I will post in my own thread when it's time with your answers and my response.


Regarding your suggestion on using a 3rd primary MOT coil in series with the paralleled ones:  the use of this coil increases the overall impedance of the whole setup and as such you have to increase a little the input voltage to compensate for the reduced input current what this increased impedance causes. It is okay that you would receive flyback energy from the 3rd coil too, question is would this give more juice than what the increased input cost?  needs testing.

You wrote earlier that the 10 V or so input voltage level is rather low with respect to the mains 110-120 V these MOT primary coils were designed for originally. Here comes again that Luc drives these coils with pulsed DC and not AC, notice the pulsed DC involves already several Amper peak currents when the voltage level is at the 10 V area, while normal AC drive at 110-120 V input would result only in some hundred mA maximum or less input current levels (assuming no load condition).

One more thing: these "transformers" have open magnetic cores, rendering the original primary coil inductances much less than a closed core insures, and add to this the bucking magnetic coupling which further reduces the resulting inductance. The I core entering the gap between the two open cores increases this lowered coil inductance as we learnt from Luc inductance measurements, this is good.

Gyula


The added impedance is peanuts compared to what the added primary will do for the two working primaries on the wheel. As I had shown in my Half Coil Syndrome videos, by adding a second coil in series, the first coil displays a much higher action through the coil where the first coil will display a much larger single polarity. This single polarity would be more advantageous in @gotolucs case where his two primaries are on "open cores" as you so well defined. Right now the open core has a primary coil that has two polarities hitting it with no where to go and I suspect there is a good portion of the combined polarities that are simply cancelling each other out in relation to the passing plate. So by adding the third primary, this pushes one of the polarities out of the first two and into the third, thus this will lower cancellation potential in the working coils and increase the attraction of the passing plate.

Also, at pulse open, the side that is always connected (third coil) will rebias the first two primaries much more fully thus preparing the coil and core for the next complete change in polarity. I know you guys stand by the never proven, but always can I say "blindly" accepted, notion that the two primaries will produce a magnetic field and it is this field that will attract the passing plate, but in Spin Conveyance theory, this is not the case. It is the iron and copper atoms that do all the work. All that is required is to produce a change in the atomic alignments and the more change that is produced the more attraction it will produce simply mass to mass without any field requirement. I will explain this further soon because I do not want to use @gotolucs thread on anything off topic.

wattsup

Hi MileHigh,

I have done a test with permanent magnets in repel configuration, the attached picture shows what kind of magnets I used. The single half crescent-shaped magnets are magnetised through their thickness, so these make up for two long "bar" magnets with the poles at the ends, I hope you accept this as if they were two long and thin bar magnets.

First I held the two "bar" magnets in my left and right hands and started to force them closer and closer together with facing repel poles and maintaining their lengthwise axis in exact alignment. I clearly felt an increasing repel force all the way till the facing surfaces actually touched each other.
These magnets are ALNICO types and I managed to fully force them together. I have some cylinder shaped Neodymium magnets but they are so strong I cannot force them fully together with facing repel poles in my hands, a gap of about 1.5-2mm remains between their facing surfaces. But as I force them closer and closer,  I do feel an increasing repel force as the gap reduces between them till I reach the 1.5-2mm gap I cannot defeat by my hands.

In the pictures I show the two Alnico "bar" magnets in repel, with the help from a family member. Top picture shows what distance they let themselves place in repel, it was about 29-30mm on the table (of course this is influenced by friction). The middle and bottom pictures show as we forced the "bar" magnets closer and closer while sensing the repel force by our fingers continuously. Any time we stopped forcing them together and let the bars toss each other out to the left and right, they always snapped backwards immediately. There was no any distance my helper or I found where the repel force would have been weaker, nor we found a position any close to each other where we could feel a no repulsion, no attraction situation.

The above text is my answer to this part of your post:

Let's do a thought experiment that anybody can replicate in real life.  You have two long and thin bar magnets, where one is slightly stronger than the other.

You set up the magnets like this:   [S============N]        [N=============S]

As the two magnets are brought together you feel increasing repulsion.  Then at a certain close distance from each other you feel nothing, no repulsion or attraction.  That is where the opposing north fields have cancelled each other out.  Then as you bring the two magnets closer together they are lightly attracted and the two north ends stick together.  This is where the stronger magnet has dominated over the weaker magnet and there is a small net magnetic field and a small attraction.

On the web there are such pieces of information like this:
"The point X is called a neutral point. The forces due to both magnets cancel each other, i.e. there is no net force, at X."

See the next attachment with the drawing belonging to that text, from this link:
http://www.animatedscience.co.uk/ks5_physics/general/Electricity%20&%20Magnetism/Magnetic%20Fields.htm

Well, I can accept that in a tiny volume like some pin-heads would represent in the middle area between the facing repel magnets, the flux lines leaving both magnets are so much diverted sideways by the mutual repulsion that there would remain only a tiny neutral point or volume as shown. However, this must be so small force cancellation that cannot affect much the resulting main repel force which comes about from flux lines leaving the magnets elsewhwere on the facing areas. At least we have not sensed any such reducement, let alone small attraction force.

I can also accept that in case the two repel magnets are different in strength like in the case of a ferrite magnet and a rare earth magnet interaction, here the stronger magnet may change the weaker magnet's original properties by remagnetizing it (changes the original poles for instance) temporarily or for a longer time.
However this may not happen with two ceramic magnets, for instance which may have but a small difference in strength.

I did not mean to consider these latter situations, especially not in the case of two repelling electromagnets which was the initial situation when I asked what you had meant by magnetic field cancellation when the coils had only air between them.

Let me copy some characteristics of magnetic lines of force from this link http://www.tpub.com/neets/book1/chapter1/1i.htm

1. Magnetic lines of force are continuous and will always form closed loops.
2. Magnetic lines of force will never cross one another.
3. Parallel magnetic lines of force traveling in the same direction repel one another. Parallel magnetic lines of force traveling in opposite directions tend to unite with each other and form into single lines traveling in a direction determined by the magnetic poles creating the lines of force.
4. Magnetic lines of force tend to shorten themselves. Therefore, the magnetic lines of force existing between two unlike poles cause the poles to be pulled together.
5. Magnetic lines of force pass through all materials, both magnetic and nonmagnetic.
6. Magnetic lines of force always enter or leave a magnetic material at right angles to the surface.

Can you agree with these points?

Gyula

PS  Next time I will try to answer some of your other statements / opinions made in your previous two posts.

1. Magnetic lines of force are continuous and will always form closed loops.
2. Magnetic lines of force will never cross one another.
3. Parallel magnetic lines of force traveling in the same direction repel one another. Parallel magnetic lines of force traveling in opposite directions tend to unite with each other and form into single lines traveling in a direction determined by the magnetic poles creating the lines of force.
4. Magnetic lines of force tend to shorten themselves. Therefore, the magnetic lines of force existing between two unlike poles cause the poles to be pulled together.
5. Magnetic lines of force pass through all materials, both magnetic and nonmagnetic.
6. Magnetic lines of force always enter or leave a magnetic material at right angles to the surface.

Can you agree with these points?

Gyula

#6 is wrong.  It looks like the author is mixed up and was actually thinking about static electric field lines leaving a conductive surface.  In that case the electric field lines have to be at right angles to the surface.